Why are orange cats more likely to be male?

The gene that determines whether a cat will have an orange coat of fur is linked to the X chromosome, one of the two sex chromosomes (X and Y) in mammals. As male cats have a single X chromosome paired with a Y chromosome, inheriting a single copy of the orange gene on the X chromosome from their mother will make them orange. In comparison, female cats possess two X chromosomes, each capable of carrying a different color gene that affects the coat. A female cat can only be orange if both her X chromosomes—one from each parent—carry the orange gene, which is relatively rare. This is why orange coloration is more commonly seen in males and only about 1 in 5 orange cats are likely to be female.

Female cats with one orange and one black color-coded X chromosome often display a calico or tortoiseshell pattern, which has patches of both colors. This phenomenon is far less common in males, as they typically have only one X chromosome, limiting their coat color to either orange or black but not both.